DOCSLIB.ORG

Adapting the Water Erosion Prediction Project (WEPP) Model for Forest Applications

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Adapting the Water Erosion Prediction Project (WEPP) Model for Forest Applications Journal of Hydrology 366 (2009) 46–54 Contents lists available at ScienceDirect Journal of Hydrology journal homepage: www.elsevier.com/locate/jhydrol Adapting the Water Erosion Prediction Project (WEPP) model for forest applications Shuhui Dun a,*, Joan Q. Wu a, William J. Elliot b, Peter R. Robichaud b, Dennis C. Flanagan c, James R. Frankenberger c, Robert E. Brown b, Arthur C. Xu d a Washington State University, Department of Biological Systems Engineering, P.O. Box 646120, Pullman, WA 99164, USA b US Department of Agriculture, Forest Service, Rocky Mountain Research Station, Moscow, ID 83843, USA c US Department of Agriculture, Agricultural Research Service (USDA-ARS), National Soil Erosion Research Laboratory, West Lafayette, IN 47907, USA d Tongji University, Department of Geotechnical Engineering, Shanghai 200092, China article info summary Article history: There has been an increasing public concern over forest stream pollution by excessive sedimentation due Received 11 July 2008 to natural or human disturbances. Adequate erosion simulation tools are needed for sound management Received in revised form 6 December 2008 of forest resources. The Water Erosion Prediction Project (WEPP) watershed model has proved useful in Accepted 12 December 2008 forest applications where Hortonian flow is the major form of runoff, such as modeling erosion from roads, harvested units, and burned areas by wildfire or prescribed fire. Nevertheless, when used for mod- eling water flow and sediment discharge from natural forest watersheds where subsurface flow is dom- Keywords: inant, WEPP (v2004.7) underestimates these quantities, in particular, the water flow at the watershed Forest watershed outlet. Surface runoff Subsurface lateral flow The main goal of this study was to improve the WEPP v2004.7 so that it can be applied to adequately Soil erosion simulate forest watershed hydrology and erosion. The specific objectives were to modify WEPP v2004.7 Hydrologic modeling algorithms and subroutines that improperly represent forest subsurface hydrologic processes; and, to WEPP assess the performance of the modified model by applying it to a research forest watershed in the Pacific Northwest, USA. Changes were made in WEPP v2004.7 to better model percolation of soil water and subsurface lateral flow. The modified model, WEPP v2008.9, was applied to the Hermada watershed located in the Boise National Forest, in southern Idaho, USA. The results from v2008.9 and v2004.7 as well as the field obser- vations were compared. For the period of 1995–2000, average annual precipitation for the study area was 954 mm. Simulated annual watershed discharge was negligible using WEPP v2004.7, and was 262 mm using WEPP v2008.9, agreeable with field-observed 275 mm. Ó 2008 Elsevier B.V. All rights reserved. Introduction however, subsurface lateral flow and channel flow are predomi- nant (Luce, 1995). When used under such forest conditions, WEPP Many areas of the world depend on forest watersheds as (v2004.7) underestimates subsurface lateral flow and discharge at sources of high-quality surface water for domestic supply, indus- the watershed outlet (Elliot et al., 1995). trial use, and agricultural production (Dissmeyer, 2000). There is WEPP was intended to be applied to agriculture, rangelands and increasing public concern over forest stream pollution by excessive forests (Foster and Lane, 1987). Runoff generation was by the sedimentation resulting from forest management activities. Ade- mechanism of rainfall-excess described by the modified Green- quate erosion simulation tools are needed for sound forest re- Ampt infiltration model (Mein and Larson, 1973; Chu, 1978). Re- source management. The Water Erosion Prediction Project cently, scientists have increasingly realized that rainfall-excess is (WEPP) model (Flanagan et al., 2001), a physically-based erosion not the only runoff-generation mechanism that influences forest prediction software program developed by the US Department of hydrology and erosion (Elliot et al., 1996; Covert, 2003). Forest Agriculture (USDA), has proved useful in areas where Hortonian lands are exemplified by steep slopes, and young, shallow, and flow dominates, e.g., in forest applications of modeling erosion coarse-grained soils, differing markedly from typical agricultural from insloped or outsloped roads, or harvested or burned areas lands. In addition, forest canopy and residue covers differ from by wildfire or prescribed fire (Elliot et al., 1999; Elliot and Tysdal, those in crop- and rangelands causing the rates and combinations 1999; Elliot, 2004; Robichaud et al., 2007). In most natural forests, of individual hydrologic processes to differ (Luce, 1995). Fig. 1 illustrates the differences in major characteristics of hydrologic * Corresponding author. Tel.: +1 509 335 5996; fax: +1 509 335 2722. processes in agricultural and forest settings. WEPP is a reasonable E-mail address: [email protected] (S. Dun). tool in quantifying runoff and erosion from typical agricultural 0022-1694/$ - see front matter Ó 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.jhydrol.2008.12.019 S. Dun et al. / Journal of Hydrology 366 (2009) 46–54 47 P P Tp Tp Es Es R Surface soil Horizon A R Weathering Horizon B layer Bedrock Horizon C R s Dp Dp (a) Agricultural (b) Forest Fig. 1. Diagram showing the difference in primary hydrologic processes between typical (a) agricultural soil profile and (b) forest setting. The size of the arrows reflects the relative magnitude or rate of the individual processes: P, precipitation; Tp, plant transpiration; Es, soil evaporation; R, surface runoff; Rs, subsurface lateral flow, and ; Dp, percolation through bottom of soil profile. fields (Laflen et al., 2004). For forest watershed applications, how- The erosion routines estimate interrill and rill erosion as well as ever, the model needs to be modified to properly represent the sediment transport in channels. The channel component consists hydrologic processes involved. Covert et al. (2005), in an applica- of channel hydrology and erosion. Channel hydrology routines gen- tion of WEPP for simulating runoff and erosion on disturbed forest erate hydrographs by combining channel runoff with the surface watersheds, emphasized the need for adequately representing lat- runoff from upstream watershed elements, i.e., hillslopes, channels eral flow processes in WEPP. or impoundments. The channel erosion routines simulate soil The main purpose of this study was to improve the WEPP detachment from channel bed and bank due to excess flow shear (v2004.7) watershed model such that it can be used to simulate stress through downcutting and widening as well as sediment and predict forest watershed hydrology and erosion. The specific transport and deposition. objectives were to identify and improve WEPP (v2004.7) subrou- tines for subsurface lateral flow process; and to assess the perfor- Simulation of subsurface water flow in WEPP mance of the modified model by applying it to a typical forested watershed in the US Pacific Northwest. WEPP conceptualizes a hillslope as a rectangular strip with a representative slope profile and multiple OFEs (Cochrane and Flan- Method agan, 2003). Rainfall excess, in intervals of minutes, is calculated as the difference between rainfall rate and infiltration estimated Model description using a modified Green-Ampt- Mein–Larson equation (Mein and Larson, 1973; Chu, 1978), with rainfall interception in the canopy WEPP partitions a watershed into hillslopes and a channel net- and residue as well as surface depression storage taken into con- work that includes channel segments and impoundments. Over- sideration. Overland flow rate on an OFE is determined from the land flow from hillslopes feeds into the channel network. A average rainfall excess of the immediately upstream, consecutively hillslope can be further divided into overland-flow elements feeding OFEs weighted by their lengths. Redistribution of infil- (OFEs), within which soil, vegetation, and management conditions trated water, including evapotranspiration (ET), percolation, and are assumed homogeneous. A recently developed geo-spatial inter- subsurface lateral flow, is simulated within each OFE on a daily ba- face, GeoWEPP, allows the use of digital elevation models (DEMs) sis. Transmission of subsurface lateral flow is between two adja- to generate watershed configurations and topographic inputs for cent OFEs. the WEPP model (Renschler, 2003). Important functions and rou- Within an OFE, a soil profile can be divided into layers of 10 cm tines in WEPP are summarized below after Flanagan et al. (1995). for the top two (for better description of surface conditions, e.g., The hillslope component of WEPP simulates the following pro- tillage effect) and 20 cm for the remainder. Soil physical properties cesses: surface hydrology and hydraulics, subsurface hydrology, for each layer, such as saturated hydraulic conductivity (Ks), field vegetation growth and residue decomposition, winter processes, capacity (hfc) and plant wilting point (hwp) (considered as the soil and sediment detachment and transport. The surface hydrology water content h at matric potential of about 30 kPa and 1.5 MPa, routines use information on weather, vegetation and management respectively), are estimated using the soil texture input. WEPP al- practices, and maintain a continuous balance of the soil water on a lows a user to define an effective saturated hydraulic conductivity daily basis. The hydraulics routine performs overland-flow routing for the top two soil layers, which
Load more

Recommended publications
  • Modifying Wepp to Improve Streamflow Simulation in a Pacific Northwest Watershed
    MODIFYING WEPP TO IMPROVE STREAMFLOW SIMULATION IN A PACIFIC NORTHWEST WATERSHED A. Srivastava, M. Dobre, J. Q. Wu, W. J. Elliot, E. A. Bruner, S. Dun, E. S. Brooks, I. S. Miller ABSTRACT. The assessment of water yield from hillslopes into streams is critical in managing water supply and aquatic habitat. Streamflow is typically composed of surface runoff, subsurface lateral flow, and groundwater baseflow; baseflow sustains the stream during the dry season. The Water Erosion Prediction Project (WEPP) model simulates surface runoff, subsurface lateral flow, soil water, and deep percolation. However, to adequately simulate hydrologic conditions with significant quantities of groundwater flow into streams, a baseflow component for WEPP is needed. The objectives of this study were (1) to simulate streamflow in the Priest River Experimental Forest in the U.S. Pacific Northwest using the WEPP model and a baseflow routine, and (2) to compare the performance of the WEPP model with and without including the baseflow using observed streamflow data. The baseflow was determined using a linear reservoir model. The WEPP- simulated and observed streamflows were in reasonable agreement when baseflow was considered, with an overall Nash- Sutcliffe efficiency (NSE) of 0.67 and deviation of runoff volume (Dv) of 7%. In contrast, the WEPP simulations without including baseflow resulted in an overall NSE of 0.57 and Dv of 47%. On average, the simulated baseflow accounted for 43% of the streamflow and 12% of precipitation annually. Integration of WEPP with a baseflow routine improved the model’s applicability to watersheds where groundwater contributes to streamflow. Keywords. Baseflow, Deep seepage, Forest watershed, Hydrologic modeling, Subsurface lateral flow, Surface runoff, WEPP.
    [Show full text]
  • Soil Erosion Prediction in the Grande River Basin, Brazil Using Distributed Modeling
    Catena 79 (2009) 49–59 Contents lists available at ScienceDirect Catena journal homepage: www.elsevier.com/locate/catena Soil erosion prediction in the Grande River Basin, Brazil using distributed modeling S. Beskow a,b,⁎, C.R. Mello b, L.D. Norton c, N. Curi d, M.R. Viola b, J.C. Avanzi a,d a National Soil Erosion Research Laboratory, 275 South Russell Street, Purdue University, 47907-2077, West Lafayette, IN, USA b Department of Agricultural Engineering, Federal University of Lavras, C.P. 3037, 37200-000, Lavras, MG, Brazil c USDA-ARS National Soil Erosion Research Laboratory, 275 South Russell Street, Purdue University, 47907-2077, West Lafayette, IN, USA d Department of Soil Science, Federal University of Lavras, C.P. 3037, 37200-000, Lavras, MG, Brazil article info abstract Article history: Mapping and assessment of erosion risk is an important tool for planning of natural resources management, Received 20 June 2008 allowing researchers to modify land-use properly and implement management strategies more sustainable in Received in revised form 25 May 2009 the long-term. The Grande River Basin (GRB), located in Minas Gerais State, is one of the Planning Units for Accepted 27 May 2009 Management of Water Resources (UPGRH) and is divided into seven smaller units of UPGRH. GD1 is one of them that is essential for the future development of Minas Gerais State due to its high water yield capacity and Keywords: potential for electric energy production. The objective of this study is to apply the Universal Soil Loss Equation Simulation (USLE) with GIS PCRaster in order to estimate potential soil loss from the Grande River Basin upstream from the Erosion fi USLE Itutinga/Camargos Hydroelectric Plant Reservoir (GD1), allowing identi cation of the susceptible areas to GIS water erosion and estimate of the sediment delivery ratio for the adoption of land management so that further Soil conservation soil loss can be minimized.
    [Show full text]
  • A Landscape Evolution Model with Dynamic Hydrology
    r.sim.terrain 1.0: a landscape evolution model with dynamic hydrology Brendan Alexander Harmon1, Helena Mitasova2,3, Anna Petrasova2,3, and Vaclav Petras2,3 1Robert Reich School of Landscape Architecture, Louisiana State University, Baton Rouge, Louisiana, USA 2Center for Geospatial Analytics, North Carolina State University, Raleigh, North Carolina, USA 3Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh, North Carolina, USA Correspondence: Brendan Harmon ([email protected]) Nota bene: since we have restructured the manuscript, the references to sections, equations, figures, and tables in our responses refer to the revised paper. 1 Reviewer 1 Comment Although the difference between steady-state and dynamic flow regimes is discussed, the differences between the 5 erosion regimes (e.g. detachment capacity limited, transport capacity limited, erosion-deposition and detachment limited) are less clear. A more thorough discussion of those regimes and their differences would allow for a clearer understanding of the results of the model compared to the typical characteristics associated with these regimes. On P16 L24 to L27, the results of SIMWE were compared to the characteristics typical of the simulated erosion regime. Establishing the characteristics of the erosion regimes earlier, perhaps after the explanation of the flow regimes, would give the reader more clarity regarding what 10 influences these regimes and how the model compares to real-world characteristics. Response We have restructured the paper and now thoroughly discuss soil erosion-deposition regimes in Section 2.1.2 with equations 6-9. 15 Comment Given that the study area has information for 2012 and 2016, one possible improvement is to compare the model results to the observed difference between those two years.
    [Show full text]
  • Erosion and Sediment Transport Modelling in Shallow Waters: a Review on Approaches, Models and Applications
    International Journal of Environmental Research and Public Health Review Erosion and Sediment Transport Modelling in Shallow Waters: A Review on Approaches, Models and Applications Mohammad Hajigholizadeh 1,* ID , Assefa M. Melesse 2 ID and Hector R. Fuentes 3 1 Department of Civil and Environmental Engineering, Florida International University, 10555 W Flagler Street, EC3781, Miami, FL 33174, USA 2 Department of Earth and Environment, Florida International University, AHC-5-390, 11200 SW 8th Street Miami, FL 33199, USA; melessea@fiu.edu 3 Department of Civil Engineering and Environmental Engineering, Florida International University, 10555 W Flagler Street, Miami, FL 33174, USA; fuentes@fiu.edu * Correspondence: mhaji002@fiu.edu; Tel.: +1-305-905-3409 Received: 16 January 2018; Accepted: 10 March 2018; Published: 14 March 2018 Abstract: The erosion and sediment transport processes in shallow waters, which are discussed in this paper, begin when water droplets hit the soil surface. The transport mechanism caused by the consequent rainfall-runoff process determines the amount of generated sediment that can be transferred downslope. Many significant studies and models are performed to investigate these processes, which differ in terms of their effecting factors, approaches, inputs and outputs, model structure and the manner that these processes represent. This paper attempts to review the related literature concerning sediment transport modelling in shallow waters. A classification based on the representational processes of the soil erosion and sediment transport models (empirical, conceptual, physical and hybrid) is adopted, and the commonly-used models and their characteristics are listed. This review is expected to be of interest to researchers and soil and water conservation managers who are working on erosion and sediment transport phenomena in shallow waters.
    [Show full text]
  • Using the Wepp Model to Predict Sediment Yield in a Sample Watershed in Kahramanmaras Region
    USING THE WEPP MODEL TO PREDICT SEDIMENT YIELD IN A SAMPLE WATERSHED IN KAHRAMANMARAS REGION Alaaddin YÜKSEL Abdullah E. AKAY Mahmut REİS KSÜ, Orman Fakültesi, Orman Mühendisliği Bölümü, 46060, Kahramanmaraş Recep GÜNDOĞAN KSÜ, Ziraat Fakültesi, Toprak Bölümü, 46060, Kahramanmaraş E-mail: [email protected], [email protected], [email protected], [email protected] ABSTRACT Considerable amount of sediment yield reaches into streams, lakes, and dam reservoirs from 26 major watersheds in Turkey. Several models have been developed to estimate the sediment yield from watersheds. WEPP (Water Erosion Prediction Project) model is one of the most common model which not only predicts the amount of sediment yield but also determines where and when the sediment produc- tion occurs and locates possible deposition places. Besides, the geo-spatial interface for WEPP model (GeoWEPP) can use digital geo-referenced information by integrat- ing with the most common GIS tools ( i.e. ArcView, ArcGIS) . Therefore, watershed managers can decide the most appropriate soil erosion conservation and sediment prevention techniques for a specific watershed based on the WEPP outputs in text or graphical format. The sediment yield from a watershed in Kahramanmaraş region (Ayvalı Dam Watershed) was estimated by using GeoWEPP model. In this study, process of estimating sediment yield from a specific sub watershed located in a for- ested area was presented to indicate the performance of GeoWEPP. This study indi- cated that using GeoWEPP can provide watershed managers with quick estimation of sediment yield from large watersheds in high accuracy. Keywords: WEPP, GeoWEPP, Sedimentation, Dam Watershed, Kahramanmaraş, 12 INTERNATIONAL CONGRESS ON RIVER BASIN MANAGEMENT 1.
    [Show full text]
  • Application of the WEPP Model to Surface Mine Reclamation• By
    Application of the WEPP Model to Surface Mine Reclamation• by W. J. Elliot Wu Qiong Annette V. Elliot2 Abstract. Sediment from mining sources contributes to the pollution of surface waters. Restoration of mined sites can reduce the problems associated with erosion, and one of the most important objectives of surface mine reclamation is the control of surface runoff and erosion from reclaimed areas. Current methods for predicting sediment yield do not suit surface mine sites because non- agricultural soils and vegetation are involved. There is a need for a computer model to aid in identifying improved management systems and reclamation practices with suitable input data files and appropriate hydrologic modeling routines. The USDA Water Erosion Prediction Project (WEPP) resulted in the development of a computer model based on fundamental erosion mechanics. The WEPP model will be in widespread use by the mid 1990s by the Soil Conservation Service (SCSI, and will be the erosion prediction model of choice well into the next century. This paper gives an overview of the WEPP erosion prediction technology and its implications to surface mine reclamation, and reports on a research project that identifies critical watershed parameters unique to surface mining and reclamation through a sensitivity analysis of the WEPP Watershed Model. The study contributes to the validation of the WEPP Watershed Version by comparing estimates generated by the model with observed data from watersheds after surface mining. Additional Key Words: Erosion simulation INTRODUCTION control of surface runoff and erosion from reclaimed areas (Mitchell et al., 1983; Hartley As renewable fossil fuel energy reserves are and Schuman, 1984).
    [Show full text]
  • Modeling Phosphorus Transport Using the WEPP Model Mario Perez-Bidegain Iowa State University
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Digital Repository @ Iowa State University Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 2007 Modeling phosphorus transport using the WEPP model Mario Perez-Bidegain Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Agriculture Commons, Agronomy and Crop Sciences Commons, Bioresource and Agricultural Engineering Commons, Environmental Sciences Commons, and the Soil Science Commons Recommended Citation Perez-Bidegain, Mario, "Modeling phosphorus transport using the WEPP model" (2007). Retrospective Theses and Dissertations. 15497. https://lib.dr.iastate.edu/rtd/15497 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Modeling phosphorus transport using the WEPP model by Mario Perez-Bidegain A dissertation submitted to the graduate faculty in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Co-majors: Soil Science (Soil Management); Environmental Science Program of Study Committee: Richard M. Cruse, Co-major Professor Matthew J. Helmers, Co-major Professor Brian K. Hornbuckle Robert Horton John M. Laflen Iowa State University Ames, Iowa 2007 Copyright © Mario Perez-Bidegain, 2007. All rights reserved. UMI Number: 3259439 UMI Microform 3259439 Copyright 2007 by ProQuest Information and Learning Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code.
    [Show full text]
  • Wepp Model Applications for Evaluations of Best Management Practices
    WEPP MODEL APPLICATIONS FOR EVALUATIONS OF BEST MANAGEMENT PRACTICES D.C. FLANAGAN 1, W.J. ELLIOT 2, J.R. FRANKENBERGER 3, C. HUANG 4 1USDA-Agricultural Research Service, National Soil Erosion Research Laboratory, 275 S. Russell Street, West Lafayette, Indiana, USA, 47907. Phone: +01 765-494- 8673, FAX: +01 765-494-5948, email: [email protected] 2USDA-Forest Service, Rocky Mountain Research Station, 1221 S. Main St., Moscow, ID, USA. 83843. Phone: +01 208-883-2338, FAX: +01 208-883-2318, email: [email protected] 3USDA-Agricultural Research Service, National Soil Erosion Research Laboratory, 275 S. Russell Street, West Lafayette, Indiana, USA, 47907. Phone: +01 765-494- 8673, FAX: +01 765-494-5948, email: [email protected] 4USDA-Agricultural Research Service, National Soil Erosion Research Laboratory, 275 S. Russell Street, West Lafayette, Indiana, USA, 47907. Phone: +01 765-494- 8673, FAX: +01 765-494-5948, email: [email protected] Summary The Water Erosion Prediction Project (WEPP) model is a process-based erosion prediction technology for application to small watersheds and hillslope profiles, under agricultural, forested, rangeland, and other land management conditions. Developed by the United States Department of Agriculture (USDA) over the past 25 years, WEPP simulates many of the physical processes that are important when estimating runoff, soil erosion, and sediment delivery at a location having unique climate, topography, soils, and plants/tillage/management. A variety of user interfaces and databases make the model very easy to apply and use, particularly within the United States. The USDA Agricultural Research Service (ARS) has developed a stand-alone Windows WEPP system, as well as internet web-based hillslope and GIS watershed interfaces.
    [Show full text]
  • WEPP Model Be Improved to Allow Access to Sub-Daily Time Scale Results So That It Can Be Better Integrated with Other Watershed Models
    A COUPLED UPLAND-EROSION AND INSTREAM HYDRODYNAMIC-SEDIMENT TRANSPORT MODEL FOR EVALUATING SEDIMENT TRANSPORT IN FORESTED WATERSHEDS W. J. Conroy, R. H. Hotchkiss, W. J. Elliot ABSTRACT. This article describes a prototype modeling system for assessing forest management-related erosion at its source and predicting sediment transport from hillslopes to stream channels and through channel networks to a watershed outlet. We demonstrate that it is possible to develop a land management tool capable of accurately assessing the primary impacts of spatiotemporally varied forest management practices on sediment yield and delivery at hillslope to watershed scales in a single simulation. The modeling system consists of four components: (1) the TOpographic ParameteriZation (TOPAZ) model for discretizing hillslope and channel elements, (2) the Water Erosion Prediction Project (WEPP) model for evaluating hillslope-scale surface erosion processes, (3) the National Center for Computational Hydrodynamics and Engineering’s one-dimensional (CCHE1D) hydrodynamic-sediment transport model, and (4) an interface program to manage relational databases and data transfer between modules. The coupled models were calibrated and validated with observed flow and sediment load data from the North Fork Caspar Creek Experimental Watershed in coastal northern California. The coupled models’ predictions of peak flow rate and total flow volume were not significantly different from observed values. Predicted sediment concentrations were significantly different from observed values, but within typical ranges for sediment transport equations. We recommend that the WEPP model be improved to allow access to sub-daily time scale results so that it can be better integrated with other watershed models. Keywords. Erosion modeling, Hydrodynamic modeling, Watershed models, TMDLs, CCHE1D, WEPP.
    [Show full text]
  • Erosion and Sediment Control for Agriculture
    Chapter 4C: Erosion and Sediment Control 4C: Erosion and Sediment Control Management Measure for Erosion and Sediment Apply the erosion component of a Resource Management System (RMS) as defined in the Field Office Technical Guide of the U.S. Department of Agriculture–Natural Resources Conservation Service (see Appendix B) to minimize the delivery of sediment from agricultural lands to surface waters, or Design and install a combination of management and physical practices to settle the settleable solids and associated pollutants in runoff delivered from the contributing area for storms of up to and including a 10-year, 24-hour frequency. Management Measure for Erosion and Sediment: Description Application of this management measure will preserve soil and reduce the mass of sediment reaching a water body, protecting both agricultural land and water quality. This management measure can be implemented by using one of two general strategies, or a combination of both. The first, and most desirable, strategy is to implement practices on the field to minimize soil detachment, erosion, and transport of sediment from the field. Effective practices include those that maintain crop residue or vegetative cover on the soil; improve soil properties; Sedimentation reduce slope length, steepness, or unsheltered distance; and reduce effective causes widespread water and/or wind velocities. The second strategy is to route field runoff through damage to our practices that filter, trap, or settle soil particles. Examples of effective manage- waterways. Water ment strategies include vegetated filter strips, field borders, sediment retention supplies and wildlife ponds, and terraces. Site conditions will dictate the appropriate combination of resources can be practices for any given situation.
    [Show full text]
  • The Water Erosion Prediction Project (WEPP) Model
    WEPP Model Background, Status, and Current Projects Dennis C. Flanagan Research Agricultural Engineer USDA-Agricultural Research Service Adjunct Professor Purdue Univ., Dept. of Agric. & Biol. Eng. National Soil Erosion Research Laboratory West Lafayette, Indiana, USA “The NSERL – to provide the knowledge and technology needed by land users to conserve soil for future generations.” Building dedicated 1/15/1982 Presentation Outline Erosion Prediction History WEPP Model Background Model Status – 2015 Current Projects Summary Scales of interest 0.01 to 1 ha – Hillslope scale Hillslope profiles in 1 to 1000 ha – Field, farm scale agricultural fields, forested areas, rangeland parcels, Small watersheds in landfills, mines, highways, agricultural fields, on farms, construction sites, etc. in forested catchments, construction sites, etc. Important Processes at these Scales Precipitation (and weather in general) – rainfall occurrence, volume, storm duration, intensity Surface hydrology – infiltration, pondage, ET, runoff Subsurface hydrology – percolation, seepage, lateral flow Hillslope erosion processes – detachment by rainfall, shallow flow transport, rill detachment by flow shear stress, sediment transport, sediment deposition. Channel erosion processes – detachment by flow shear stress, sediment transport, downcutting to a nonerodible layer, sediment deposition. Hillslope region from a small watershed Erosion Prediction History Early tools developed in the 1940’s-1970’s were all empirically-based. Universal Soil Loss Equation (USLE) and revisions Beginning in late 1970’s, efforts began to focus on process-based modeling. ANSWERS and CREAMS models were first distributed parameter hillslope/watershed models with some physical processes represented. They still used USLE for sediment generation. In 1985, the Water Erosion Prediction Project (WEPP) was initiated by USDA, at a meeting in Lafayette, Indiana.
    [Show full text]
  • Application of the Wind Erosion Prediction System in the Airpact Regional Air Quality Modeling Framework
    APPLICATION OF THE WIND EROSION PREDICTION SYSTEM IN THE AIRPACT REGIONAL AIR QUALITY MODELING FRAMEWORK S. H. Chung, F. L. Herron-Thorpe, B. K. Lamb, T. M. VanReken, J. K. Vaughan, J. Gao, L. E. Wagner, F. Fox ABSTRACT. Wind erosion of soil is a major concern of the agricultural community, as it removes the most fertile part of the soil and thus degrades soil productivity. Furthermore, dust emissions due to wind erosion degrade air quality, reduce visibility, and cause perturbations to regional radiation budgets. PM10 emitted from the soil surface can travel hundreds of kilometers downwind before being deposited back to the surface. Thus, it is necessary to address agricultural air pollutant sources within a regional air quality modeling system in order to forecast regional dust storms and to understand the im- pact of agricultural activities and land-management practices on air quality in a changing climate. The Wind Erosion Prediction System (WEPS) is a new tool in regional air quality modeling for simulating erosion from agricultural fields. WEPS represents a significant improvement, in comparison to existing empirical windblown dust modeling algorithms used for air quality simulations, by using a more process-based modeling approach. This is in contrast with the empirical approaches used in previous models, which could only be used reliably when soil, surface, and ambient conditions are similar to those from which the parameterizations were derived. WEPS was originally intended for soil conservation ap- plications and designed to simulate conditions of a single field over multiple years. In this work, we used the EROSION submodel from WEPS as a PM10 emission module for regional modeling by extending it to cover a large region divided in- to Euclidean grid cells.
    [Show full text]